Genes, enzymes and secondary metabolites in industrial microorganisms. The 1995 Thom Award Lecture.

Apparently contrasting approaches, ie genetic engineering and screening of new microorganisms, play essential complementary roles to develop current industrial microbiology. Three topics, production and modification of milk-clotting proteinases by genetic engineering, hormonal control of secondary metabolism in streptomycetes, and screening of bioactive metabolites, are introduced as cases of such a hybrid approach, while symbiotic microorganisms are discussed as an example of the vast terra incognita still remaining for the future microbiology.